Abstract: There is provided a low vibration-type saw blade including a circular steel substrate having a center hole at a central portion thereof, a super abrasive grain layer which includes diamond abrasive grains or CBN abrasive grains and is continuously formed to an outer periphery edge of the steel substrate, and a pair of male and female flanges which are made of a fiber reinforced plastic and have an attachment hole to an electric tool spindle at a central portion, and which are integrally provided on a substantial half part of the steel substrate in a direction toward an outer periphery thereof through the center hole provided at the center portion of the steel substrate such that the male and female flanges sandwich the steel substrate from both side faces thereof.

Abstract: There is provided a mounting member to be detachably screwed onto the rotary shaft of a power tool, and during the attachment and detachment of the mounting member to and from the power tool, a part for clamping and integrally securing a rotary cutter between an inner flange and an outer flange which functions as a lock nut is constructed by fitting a claw of the inner flange onto a fitting groove formed in the outer flange. Owing to this construction, it is possible to highly precisely and integrally secure the mounting member to individual rotary cutters.

Abstract: A method of stirring molten metal by repeatedly sucking and rapidly discharging part of the molten metal into and out of a refractory cylinder having a lower opening end immersed in the molten metal in a ladle, comprises operating the stirring under a condition that an inner diameter (d) of the refractory cylinder is less than 1,000 mm, a relation between the inner diameter (d, mm) of the refractory cylinder and weight (W, ton) of the molten metal in the ladle is d/W.sup.0.5 >30, and an immersed depth of the refractory cylinder is within 200-700 mm. A pressurized gas for discharging the sucked molten metal out of the cylinder is introduced thereinto in an inclined direction relative to a vertical line against a point on an opposite inner wall of the cylinder at least 500 mm above the maximum suction level of the molten metal in the cylinder.

Abstract: A method of refining molten metal with stirring in a refining vessel by repeated operation of suction and discharge is disclosed, wherein a lower end of a refractory cylinder is immersed into a molten metal bath in the vessel and an inside of the cylinder opposite to the immersed end is alternately subjected to evacuation and pressurization. In this method, maximum and average values of pressure reduction velocity to be applied to the inside of the cylinder are limited to not more than 1,000 mmHg/sec and not more than 500 mmHg/sec, respectively, and an evacuation time is extended over at least 1.5 times intrinsic oscillation period of up and down movement of molten metal column inside the cylinder.